Flying Through a Geomagnetic Storm

Glowing green and red, shimmering hypnotically across the night sky, the aurora borealis is a wonder to behold. Longtime sky watchers say it is the greatest show on Earth


It might be the greatest show in Earth orbit, too. They move like a living 'shag carpet' of lights. He and other members of the crew video-recorded the displays, producing footage that officials say is some of the best-ever taken from Earth orbit. "But this expedition is not over yet," he points out hopefully. He was the science officer for ISS expedition 6 back in 2003 when the auroras were even stronger than they were now. Solar activity is now trending upward with a maximum expected in early 2013. This means the greatest show on Earth -- and in Earth orbit -- is about to get even better "We fly right over them. "Perhaps it is because I have been up here so long. That's exactly what happened in late January 2012, when a sequence of M-class and X-class solar flares sparked a light show that Pettit says he won't soon forget. "It is not disorienting to see auroras underfoot," he says. Indeed, more auroras are in the offing. "Red auroras reach all the way up to our altitude 400 km above Earth," says Pettit. It was simply amazing. "
Auroras are caused by solar activity. You should be looking up for meteors not down. Gusts of solar wind and coronal mass ejections strike Earth's magnetic field, rattling our planet's protective shell of magnetism. The videos capture the full range of aurora colors -- red, green, and many shades of purple. "
What he does find disorienting is the meteors. "
Pettit is a skilled astrophotographer. The physics is akin to what happens in the picture tube of a color TV. High above our planet, astronauts onboard the International Space Station (ISS) have been enjoying an up-close view of auroras outside their windows as the ISS flys through geomagnetic storms. "The auroras could be seen [as brightly as] city lights on the Earth below -- and even in the day-night terminator of the rising and setting sun. "
Surprisingly, Pettit does not find this unsettling. "It's like being shrunk down and put inside of a neon sign. Sometimes, when solar activity is high, the ovals expand, and the space station orbits right through them. "
"Green emissions, on the other hand, tend to stay below the space station," he says. Incoming particles are guided by Earth's magnetic field to a pair of doughnut-shaped regions called "auroral ovals. "We can actually fly into the auroras," says eye-witness Don Pettit, a Flight Engineer for ISS Expedition 30. This causes charged particles to rain down over the poles, lighting up the atmosphere where they hit. The precise color at any altitude depends on the temperature and density of the local atmosphere. "
As marvelous as these sights are, Petit has seen better. "Sometimes you feel like you can reach out and touch them. These hues correspond to different quantum transitions in excited atoms of oxygen and nitrogen. Following some recent years of deep quiet, the sun is waking up again. "Occasionally we see a meteor burning up in the atmosphere below -- and this does look strange. " There's one around the North Pole and one around the South.